Middle and Upper Pleistocene Fluvial Evolution of the Meurthe and Moselle Valleys in the Paris Basin and the Rhenish Massif ⅲ
Quaternaire, 16, (3), 2005, p. 201-215 MIDDLE AND UPPER PLEISTOCENE FLUVIAL EVOLUTION OF THE MEURTHE AND MOSELLE VALLEYS IN THE PARIS BASIN AND THE RHENISH MASSIF Ⅲ Stéphane CORDIER*, Manfred FRECHEN**, Dominique HARMAND*** and Monique BEINER**** ABSTRACT The terrace systems of the River Meurthe (Me), and the River Moselle (M) downstream from the present Moselle-Meurthe confluence are composed of eight stepped alluvial terraces (Me8-M8 to Me1-M1), situated at less than 90 m above the modern floodplain Me0-M0. Morphological, mineralogical and petrographical studies evidence that the oldest five terraces (Me8-M8 to Me4-M4) were formed by the “Palaeo-Meurthe”, while the Upper Moselle flowed towards the Meuse valley. Downstream from the confluence, the three youngest alluvial terraces (Me3-M3 to Me1-M1) contain crystalline sediments from the Upper Moselle basin; they have been formed since the Upper Moselle capture, dated about 250-270 ka before present. IRSL and radiocarbon datings provide independent absolute age control for these post-capture terraces, which respectively correlate with the end of the Saalian (Me3-M3) and the Weichselian (Me2-M2 and Me1-M1). The constant relative height of the terraces between France, Luxemburg and Germany gives evidences that there was no differenciated tec- tonic movements along the valley since at least the capture. A cyclic evolution scheme for the formation of the terraces is presented. The main gravel sedimentation occurred during cold periods (pleniglacial and late glacial phases), with a minor erosive period at the beginning of late glacial periods. Major incision occurs at the warm-to-cold transition. Key-words: Meurthe and Moselle valleys, alluvial terraces, alluvial sequences, IRSL datings, heavy minerals, Upper and Middle Pleistocene.
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